Method for dish reflector illumination via sub-reflector assembly with dielectric radiator portion

Abstract

A unitary dielectric block is provided having a waveguide transition portion located at a first end of the unitary dielectric block, a sub-reflector support portion located at a second end of the unitary dielectric block, and a radiator portion between the waveguide transition portion and the sub-reflector support portion. The unitary dielectric block may have a longitudinal axis. The sub-reflector support portion may have a proximal surface and a distal surface. The distal surface may be located further from the longitudinal axis of the unitary dielectric block than the proximal surface. The distal surface may be angled at a first angle with respect to the longitudinal axis of the unitary dielectric block, and the proximal surface may be angled at a second angle with respect to the longitudinal axis of the unitary dielectric block. The second angle may be greater than the first angle.

The invention claimed is: 
     
       1. An apparatus comprising:
 a unitary dielectric block having a waveguide transition portion located at a first end of the unitary dielectric block, a sub-reflector support portion located at a second end of the unitary dielectric block that is opposite from the first end, and a radiator portion between the waveguide transition portion and the sub-reflector support portion; and 
 a waveguide coupled between a dish reflector of a reflector antenna and the unitary dielectric block, 
 wherein the waveguide is and aligned with a longitudinal axis of the unitary dielectric block, 
 wherein the sub-reflector support portion comprises a proximal surface and a distal surface, 
 wherein the distal surface is located further from the longitudinal axis of the unitary dielectric block than the proximal surface, 
 wherein the distal surface is angled at a first angle with respect to the longitudinal axis of the unitary dielectric block, 
 wherein the proximal surface is angled at a second angle with respect to the longitudinal axis of the unitary dielectric block, and 
 wherein the second angle is greater than the first angle. 
 
     
     
       2. The apparatus of  claim 1 , wherein the sub-reflector support portion has a peripheral reference surface located further from the longitudinal axis of the unitary dielectric block than the distal surface. 
     
     
       3. The apparatus of  claim 2 , wherein the peripheral reference surface is normal to the longitudinal axis of the unitary dielectric block. 
     
     
       4. The apparatus of  claim 1 , further comprising a sub-reflector attached to the sub-reflector support portion. 
     
     
       5. The apparatus of  claim 4 , wherein the sub-reflector comprises a radiofrequency (RF) reflective coating applied to the sub-reflector support portion. 
     
     
       6. The apparatus of  claim 4 , wherein the sub-reflector comprises a metallic disk seated upon the sub-reflector support portion. 
     
     
       7. The apparatus of  claim 1 , wherein the unitary dielectric block is inserted into the waveguide up to a shoulder of the waveguide transition portion. 
     
     
       8. The apparatus of  claim 7 , wherein the unitary dielectric block is dimensioned to operate in a desired microwave frequency band, and wherein the shoulder is at least 0.75 wavelengths of a radiated wave having a frequency at a midpoint of the desired microwave frequency band. 
     
     
       9. The apparatus of  claim 1 , wherein the unitary dielectric block is dimensioned to operate in a desired microwave frequency band, and wherein a diameter of the sub-reflector support portion is at least 2.5 wavelengths of a radiated wave having a frequency at a midpoint of the desired microwave frequency band. 
     
     
       10. A method comprising:
 providing a dish reflector; 
 providing a unitary dielectric block having a waveguide transition portion located at a first end of the unitary dielectric block, a sub-reflector support portion located at a second end of the unitary dielectric block that is opposite from the first end, and a radiator portion between the waveguide transition portion and the sub-reflector support portion, wherein the sub-reflector support portion comprises a proximal surface and a distal surface, wherein the distal surface is located further from a longitudinal axis of the unitary dielectric block than the proximal surface, wherein the distal surface is angled at a first angle with respect to the longitudinal axis of the unitary dielectric block, wherein the proximal surface is angled at a second angle with respect to the longitudinal axis of the unitary dielectric block, and wherein the second angle is greater than the first angle; 
 coupling a first end of a waveguide to the dish reflector; 
 aligning a longitudinal axis of the unitary dielectric block with the waveguide; and 
 coupling the unitary dielectric block to a second end of the waveguide. 
 
     
     
       11. The method of  claim 10 , wherein the sub-reflector support portion has a peripheral reference surface located further from the longitudinal axis of the unitary dielectric block than the distal surface. 
     
     
       12. The method of  claim 11 , wherein the peripheral reference surface is normal to the longitudinal axis of the unitary dielectric block. 
     
     
       13. The method of  claim 10 , further comprising attaching a sub-reflector to the sub-reflector support portion. 
     
     
       14. The method of  claim 13 , wherein the sub-reflector comprises a radiofrequency (RF) reflective coating applied to the sub-reflector support portion. 
     
     
       15. The method of  claim 13 , wherein the sub-reflector comprises a metallic disk seated upon the sub-reflector support portion. 
     
     
       16. The method of  claim 13 , wherein coupling the unitary dielectric block to a second end of the waveguide comprises inserting the unitary dielectric block into the waveguide up to a shoulder of the waveguide transition portion. 
     
     
       17. A method comprising:
 selecting dimensions for a unitary dielectric block having a waveguide transition portion located at a first end of the unitary dielectric block, a sub-reflector support portion located at a second end of the unitary dielectric block that is opposite from the first end, and a radiator portion between the waveguide transition portion and the sub-reflector support portion, wherein the dimensions are selected based on a desired operating frequency, wherein the waveguide transition portion is dimensioned to couple with a distal end of a waveguide, wherein the sub-reflector support portion comprises a proximal surface and a distal surface, wherein the distal surface is located further from a longitudinal axis of the unitary dielectric block than the proximal surface, wherein the distal surface is angled at a first angle with respect to the longitudinal axis of the unitary dielectric block, wherein the proximal surface is angled at a second angle with respect to the longitudinal axis of the unitary dielectric block, and wherein the second angle is greater than the first angle; and 
 manufacturing the unitary dielectric block based on the selected dimensions. 
 
     
     
       18. The method of  claim 17 , wherein the manufacturing comprises machining the unitary dielectric block, and wherein a periphery of a distal surface of the unitary dielectric block that is normal to the longitudinal axis of the unitary dielectric block is dimensioned such that the periphery provides a reference surface. 
     
     
       19. The method of  claim 17 , wherein the manufacturing comprises injection molding. 
     
     
       20. The method of  claim 17 , further comprising attaching a sub-reflector to the sub-reflector support portion.